1. Field of the Invention
The present invention relates to a drawing apparatus, and a method of manufacturing an article.
2. Description of the Related Art
As a drawing apparatus used to manufacture a device such as a semiconductor integrated circuit, Japanese Patent No. 4858745 proposes an apparatus that performs pattern drawing on a substrate using a plurality of electron beams arrayed regularly to increase the productivity. The drawing apparatus described in Japanese Patent No. 4858745 modulates the dose of each of the regularly arrayed electron beams to draw a pattern in an arbitrary shape at an arbitrary position by the electron beam.
The drawing apparatus described in Japanese Patent No. 4858745 arrays the plurality of electron beams on the substrate, and adjusts the tones of drawing pixels formed at an equal pitch by modulating these electron beams, thereby drawing an arbitrary pattern on the substrate. A state of the drawing will be described with reference to FIGS. 1A and 1B. Electron beams B1, B2, and B3 are designed to be arrayed at a pitch of 10 nm. Intensity profiles of the electron beams B1 to B3 in the drawing pixels corresponding to the electron beams B1 to B3 are referred to as P1, P2, and P3, respectively. A combined intensity profile (dose distribution) obtained by summing P1 to P3 is referred to as SUM_P. As shown in FIG. 1A, if the electron beams B1 to B3 are arrayed as designed, a resist pattern whose width, that is, line width of a region in which SUM_P is equal to or larger than a development threshold RT of a resist is 20 nm is formed at a predetermined position by setting the intensities of P1 and P3 to 50% of that of P2. In addition, if the intensities of P1 and P3 are set to 100% of that of P2, a resist pattern having the line width of 30 nm is designed to be formed.
In reality, however, the electron beams B1 to B3 are not arrayed at a pitch of 10 nm as designed, but arrayed with errors as shown in FIG. 1B. Therefore, the target combined intensity profile (dose distribution) SUM_P cannot be obtained, and a resist pattern with different line width and formation position is formed. It is impossible to faithfully form a resist pattern corresponding to a design pattern.